Electric switch and method of making



June 13, 1961 c, ALLISON 2,988,606

ELECTRIC SWITCH AND METHOD OF MAKING Filed Dec. 19, 1957 2 Sheets-Sheet1 IN VEN TOR.

Kenneth CAllison June 13, 1961 c, ALLISON 2,988,606

ELECTRIC SWITCH AND METHOD OF MAKING Filed Dec. 19, 1957 2 Sheets-Sheet2 v Z; /24 22 m 29 5m 2N2 Va 39 22' 2a 2/ fg Z4 Z5 QMW 1 Imam? I. A/ZzsmHill A m 26 zaiz4 26 /2g M United States Patent Ofiice 2,988,606Patented June 13, 1961 2,988,606 ELECTRIC SWITCH AND METHOD OF MAKINGKenneth C. Allison, Crystal Lake, 111., assignor, by mesne assignments,to CTS Corporation, Elkhart, Ind., a corporation of Indiana Filed Dec.19, 1957, Ser. No. 703,980

19 Claims. (Cl. 200-11) The present invention relates to switches of thetype having multiple contacts secured to a fixed stator of insulatingmaterial so as to present free end portions for sequential engagement bya movable contact or contacts supported for travel along a predeterminedpath containing said free end portions of the stator contacts.

It is an object of this invention to provide a switch of the typeindicated which incorporates structural characteristics that not onlysimplify the construction and assembly of the switch but also improvethe quality of the switch from the standpoint of stability and freedomfrom servicing problems.

Other objects and advantages of the invention will be apparent from thefollowing description and the accompanying drawings, wherein:

FIG. 1 illustrates the manner in which the stator contacts of a rotaryswitch embodying the present invention are all simultaneously producedby simply punching out a blank of conductive material, and also showingthe manner in which these contacts are mounted in the insulating body ofthe stator.

FIG. 2 is an edge view of the structure shown in'FIG. 1, with partsbroken away and in section.

FIG. 3 illustrates one example of a finished stator contact unitdeveloped from the structure shown in FIGS. 1 and 2 for use as aone-pole sixteen position rotary switch, wherein an annular ground ringor common contact is supported from the body of the stator inside thecircle of spaced individual contacts, by an arm which is embedded in thebody as are the other stator contacts.

FIG. 4 illustrates a finished stator contact unit of modified designhaving two separate common or grounding contacts, each supported fromthe body of the stator by a plurality of arms integral therewith andembedded in the body.

FIG. 5 illustrates a rotary switch unit wherein a rotor assemblyembodying the present invention is combined with a modified form ofstator contact unit somewhat similar to that shown in FIGURE .4, with aportion of the stator broken away to illustrate the relative arrangementof the rotor and its associated contacts.

FIG. 6 is a sectional view through FIGURE 5 on the plane of line 66.

FIG. 7 is an end elevational view of a one of the rotor contact membersshown in FIG. 6.

FIG. 8 is a sectional view similar to FIG. 6 but showing a rotor contactmember and rotor assembly of modified form.

FIG. 9 is an end elevational view of the rotor contact member shown inFIG. 8.

FIG. 10 is a plan view shown in FIGS. 8 and 9.

FIG. 11 shows a further modified form of rotor contact member; and

FIG. 12 is a detail fragmentary view of the hub portion of the rotor toshow a detail of its construction.

A rotary switch incorporating features of design and construction ascontemplated by the present invention is illustrated in the drawings,the stator of which comprises a series of contacts 10 defined by endportions of a plurality of metallic strips 9 embedded in fixedspoke-like arrangement in an annular body 1 2 of non-conductive moldablematerial such, for example, as Bakelite. The strips 9 are preferablymade by stamping perforationsmll of the rotor contact member inner edge12' in a fiat metal blank so as to produce a perforated blank whereinthe outer ends of the strips are joined by an outer peripheralconnecting section 13 and the inner ends of the strips are joined by aninner connecting section 14. The blank while in such state is mounted ina suitable mold (not shown) wherein the annular stator body 12 is castabout the stator contact forming strips. As seen in the righthandportion of FIGURE 1, the width of the stator body, i.e., its radialdimension from its inner edge to its outer periphery, is less than theradial distance between the connecting sections -13 and 14. Tabs 15projecting inwardly from the inner connecting section 14 toward but fora distance short of the section 13 are partially embedded in the statorbody 12.

After the stator body is hardened from its molten state, the connectingsections 13 and 14 are severed along selected lines whereby the embeddedstrips present a circular row of spaced contacts 10 projecting radiallyinwardly from the inner edge 12' of the stator body 12 and outwardlyextending terminals or soldering lugs 16.

As will be observed in FIG. 3, one of the strips designated 9 supportsan annular common contact 10a in concentric and radially inwardly spacedrelation to the extremities of the contacts 10, the terminal 16' forthis common contact being provided by the outer end of the strip 9. Thecommon contact 10a is severed from the inner connecting section 14 on acircular line in spaced concentric relation to the inner edge of thestator body so that its sole connection with the stator body is throughthe strip or supporting arm 9' which is integral therewith. Ifadditional support for the common contact 10a is needed, certain of thetabs 15 may be left connected thereto. This will support the commoncontact at spaced points along its length, as shown in FIGURE 4 whereintwo arcuate common contacts 10b are substituted for the single annularcommon contact 10a of FIGURE 3. Thus, the arrangement of contacts 10 and10a in FIG- URE 3 provides for a single-pole sixteen-position rotaryswitch with the positions 22 /2" apart, whereas the arrangement ofcontacts 10 and 1% shown in FIGURE 4 provides a double-pole six-positionrotary switch with the positions 30 apart.

It is a significant feature of this invention that the common contact,whether it be annular as in FIGURE 3 or arcuate as in FIGURE 4, lies infront of one or more of the individual contacts, and that all of thecontacts, common as well as individual, and also the supporting arm orarms for the common contact or contacts, are coplanar, and lie in acommon plane which intersects the of the annular body 12 and is parallelto and equispaced from the opposite sides or faces thereof.

The inner edge 12' is preferably a straight-walled bore as shown, andsince its diameter is considerably greater than the thickness of thebody 12, the edge 12 may be regarded as an elongated surface.

The rotor or movable contact carrier of the switch is designatedgenerally by the numeral 17. It comprises a circular disc like unithaving a diameter slightly smaller than the inside of the annular stator12 and a thickness substantially equal to that of the stator. It isrotatably held in place within the stator by the reception of the flatcoplanar stationary contacts in a groove 18 formed in the rotor andopening to its periphery. This groove is equispaced from the oppositefaces or sides of the rotor, and its month which is the narrowest partthereof is but slightly wider than the thickness of the coplanarstationary contacts. Hence, the opposite sides or faces of the rotor areflush with those of the stator.

The rotor unit 17 consists of two identical sections molded of suitableinsulating material. Each section has a hub 20, a flange 2 1 projectingfrom the hub, a rim 22 and spokes 23 connecting the rim with the flange.The

3 hubs 20 of the two rotor sections abut and their combined thickness isequal to that of the stator 12. The abutment of the hubs results in theformation of the groove 18 since the flanges, the rims and theconnecting spokes are all narrower than the hubs and have their outerfaces flush with those of the hubs.

Any suitable means may be provided to secure the rotor sectionstogether, as for instance, a pair of pronglike fingers 24 projectingfrom the inner flat face of each hub and received in a mating socket 25.Since both sections are identical, each has a pair of these prong-likefingers and a socket, the fingers and the sockets of each section beingdiametrically opposite one another; and to effect their purpose ofsecuring the sections together, the fingers have hooks 26 on theirextremities which snap over shoulders 27 in the sockets.

Since the spokes 23, like the flanges 21, are narrower in the axialdirection than the rims 22, the groove 18 has a reentrant cross sectionwith the mouth of the groove defined by the opposed edges of the rimsbeing the narrowest part of the groove.

As will appear hereinafter, it will be convenient to consider the outerperipheral surfaces of the rims 22 and the inner circular surface of thestator 12, contiguous edges of the rotor and stator, respectively, ormore broadly, of the movable and stationary contact carriers.

Obviously, the rotor carries one or more bridging contactors 28, each ofwhich is preferably a unitary stamping. In the switch shown in FIGURESand 6, each bridging contactor comprises two U-shaped contacts 29 and30, the bights of which are integral portions of a curved base oranchoring strap 31. The arms of the U-shaped contacts are resilient andbiased towards each other so that the contacts 29 and 30 may beconsidered jaws between which the stationary contacts are gripped, andto facilitate movement of the contactor from one switching position toanother, the extremities of the arms are cupped or rounded as shown.

Since the purpose of the contactors is to selectively bridge the commonstationary contact with any one of the individual stationary contactsspanned by the common contact, the arms of the contact or jaw 29 arelonger than the arms of the contact or jaw 30, and the contactors are soplaced in the rotor that the extremities of the long jaws 29 travel inan orbit to have gripping engagement successively with the individualstationary contacts 10, whereas the extremities of the short jaws 39travel in a path coincident with the arcuate common contacts 100. Hence,as the rotor is turned, each bridging contactor will electricallyconnect a common stationary contact with first one and then another ofthe individual contacts spanned by the common contact.

As is conventional in this art, detent means (not shown) are provided toidentify the various switching positions of the rotor, but the detentmeans forms no part of this invention, and in fact is a separate unitextraneously connected to the stator and the actuating shaft, not shown.

The bridging contactors 28 are wholly confined within the groove 18, andare held in place by having their bases or connecting straps 31 confinedbetween the side of the hubs 20 which together form the bottom of thegroove, and lugs or bosses 3 2. projecting from the flanges 21. The lugsor bosses 32 are located at the junctions of the spokes 23 with theflanges, and the spacing between the long and short U-shaped contacts orjaws 29 and 30 is such that they lie between angularly adjacent lugs orbosses. This not only constrains the contactors to move with the rotoras it is turned, but also places the contact portions thereof betweenthe spokes where they may be reached for adjustment even after theentire switch is assembled.

As will be apparent, it is necessary during assembly of the switch tofirst place the bridging contactors on the stationary contacts and thenengage the rotor sections therewith and with each other, making certainthat the bridging contactors are properly oriented before the rotorsections are secured together.

An important feature of the rotor construction is that the lugs orbosses 32 are so spaced with respect to one another and the hubs 20 thatthe contactors have a degree of freedom to adjust themselves to thestationary contacts without restraint from the rotor.

As noted hereinbefore, the contactors 28 lie wholly within the rotorunit so that the spokes 23 and the rims Z2 cooperate to shield all thecontacts of the switch against damage incidental to shocks and pressuresincurred during assembly, or when the switch is in actual service. Thisdisposition of all of the contacts, both stationary and movable, withinthe stator and rotor bodies, gives the switch fiat opposite faces.Hence, a number of the switches may be axially stacked directly againstone another to be actuated by a single shaft without danger of havingthe contacts or terminals of the several switches come into contact.Such close stacking of the switches achieves optimum compactness.

FIGURE 8 illustrates another way of axially stacking at least twoseparate rotary switches. The stators of each of these two switches areidentical and are like that employed in the rotary switch of FIGURES 5and 6. Also, in essence, the rotor of this modified embodiment of theinvention is similar to that of the switch shown in FIGURES 5 and 6,i.e. it also consists of two like complementary rotor sections heldassembled by the interengaging hooks and shoulders shown in FIGURE 12.

However, in this case the flanges 21 are spaced apart a greater distanceand, accordingly, the pockets in which the bridging contactors areseated are axially much longer. The principal difference resides in theconstruction of the bridging contactors and in the provision of a spacerring 35 encircling the hub portions of the two rotor sections andconfined between shoulders thereon.

As best seen in FIGURE 10, the spacer 35 has radially outwardlyprojecting arms 36, the sides of which are grooved as at 37 to providerecesses which align with the pockets in the rotor sections and coactwith the lugs or bosses 32 to hold the rotor-carried bridging contactorsproperly assembled with the rotor. The contacts of each of thecontactors are axially aligned in this case, and comprise an upper pairof long jaws 38 to selectively grip the contacts 10 of the upper statoras the rotor is turned, and a lower pair of shorter jaws 39 to coastwith the common contact of the lower stator.

Preferably, one of the long upper jaws 38 and one of the short lowerjaws 39 are connected by a strap 40 integral therewith, while the otherupper long jaw 38 and the other lower short jaw 39 are connected by astrap 41. The two straps 40 and 41 are, in turn, secured together.

Obviously, of course, certain of the rotor carried contactors of thetandem connected switches of FIGURE 8, may she like those of the switchshown in FIGURES 5 an I-n FIGURE 11, a rotor contactor is illustratedwhich is similar to that employed in the switch of FIGURE 8, butmodified to the extent that it includes a second pair of lower jaws 42,circumferentially oifset from the jaws 39, but connected thereto by alateral branch or extension 43 integral with the strap 40. Thiscontactor thus may be said to combine the functions of the contactorsshown in FIGURES 7 and 9.

What is claimed is:

1. An electric switch having a stator member and a movable switch memberand cooperating contacts on said members including first and secondstator contacts arranged in spaced planes parallel to the path ofmovement of said movable switch member, and a rotor contactsimultaneously engageable with said first and second stator contacts,said rotor contact comprising a first strip and a second strip eachfolded upon itself to provide a first jaw and a second jaw joined at oneend by a base with the jaws of the first strip in straddling relation tothe jaws of the second strip whereby the first stator contact isengageable between the first jaw of the first strip and the first jawofthe second strip and the second stator contact is engageable between thesecond jaw of the first strip and the second jaw of the second strip.

2. An electric switch according to claim 1 wherein the base of one ofsaid strips has an integral branch terminating in a pair of jaws withwhich the second stator contact is engageable.

3. An electric switch comprising: a stationary contact carrier ofinsulating material having an elongated surface transverse to and lyingbetween two parallel planes; a plurality of individual spaced stationarycontacts fixed to the stationary contact carrier and projecting fromsaid surface thereof, said individual stationary contacts being arrangedin a row along said surface and lying in a common planes whichintersects said surface; a common stationary contact; supporting meansintegral with the common stationary contact and fixed to said carriermounting the common stationary contact in a position extending alongsaid surface of the carrier but farther therefrom than the extremitiesof the individual stationary contacts and with a part thereof oppositeand spaced from at least one of said individual contacts; a movablecontact carrier of insulating material in front of and movable alongsaid surface of the stationary contact carrier; and a bridging contactorcarried by the movable contact carrier, said bridging contactor havinglong and short contact engaging portions, the latter moving in a path tohave circuit making engagement with said common stationary contact andthe former moving in a path to be selectively engageable with theindividual stationary contacts as the movable contact carrier isactuated to selectively electrically connect the individual stationarycontacts with the common stationary contact.

4. The electric switch of claim 3, wherein said com mon stationarycontact is long enough to span a number of the stationary contacts andwherein the supporting means for the common. stationary contactcomprises a plurality of spaced arms integral therewith, each armprojecting from said surface of the stationary contact carrier betweenand in spaced relation to two of the individual stationary contacts.

5. The electric switch of claim 3, wherein the movable contact carriercomprises a pair of complementary sections shaped to jointly form agroove opening towards the stationary contact carrier and a retainingpocket, the groove accommodating the stationary contacts and the pockethaving a part of the movable contactor seated therein; and meanssecuring said complementary sections together.

6. The electric switch of claim 5, wherein the pocket is large enough toallow the contactor limited movement with respect to its carrier to thusafford the contactor a degree of freedom to adjust itself to thestationary contacts as the switch is actuated.

7. A multiposition electric switch comprising cooperating relativelymovable contact carriers of insulating material having contiguous edges,one of said contact carriers having a groove extending along and Openingto its contiguous edge so that said groove is substantially closed bythe contiguous edge of the other contact carrier; a row of spacedcontacts projecting from the contiguous edge of said other contactcarrier and into said groove, all of said contacts being fiat andcoplanar and the mouth of said groove being defined by parallel lipsspaced a distance slightly greater than the thickness of said flatcoplanar contacts so that the reception of the contacts in the mouth ofthe groove holds the contact carriers against relative movement indirections transverse to the faces of the contacts; abutting surfaces onthe contact carriers holding the same against separation in a directionparallel to said coplanar contacts and coacting with the reception ofthe contacts in the mouth of the groove to secure the contact carriersin assembled relation and constrain them to relative movement alongtheir continguous edges; and a contactor in the groove of the groovedcarrier selectively engageable with said spaced coplanar contacts byrelative motion of the contact carriers.

8. A multiposition electric switch comprising: cooper ating relativelymovable first and second contact carriers of insulating material havingcontiguous edges; means constraining said contact carriers to relativemovement along their contiguous edges; the first contact carrier havinga groove extending along its said edge and opening towards thecontiguous edge of the second contact carrier to be substantially closedthereby; a plurality of individual contacts fixed to the second contactcarrier and projecting in a row from said edge thereof into the groovein the first contact carrier, all of said individual contacts being flatand coplanar; an elongated flat common contact long enough to span aplurality of the spaced individual contacts; a supporting arm for thecommon contact integral therewith and fixed to the second contactcarrier to support the common contact from the second contact carrier,said supporting arm being flat and coplanar with the individual contactsand spaced from the nearest thereof and holding the common contactcoplanar with the individual contacts in edgewise spaced relation to theends of those of said individual contacts spanned by the common contactso that the common contact is also inside the groove in the firstcontact carrier; and a bridging contactor supportingly connected withthe first contact carrier and disposed inside the groove therein, saidbridging contactor having contact engaging portions spaced differentdistances from the mouth of the groove corresponding to the spacingbetween the common contact and the adjacent individual contacts, toselectively electrically connect different individual contacts with thecommon contact upon relative motion of the contact carriers.

9. In a multiposition electric switch: a contact carrier of insulatingmaterial; a row of spaced individual contacts fixed to the carrier andprojecting therefrom, all of said spaced individual contacts being fiatand coplanar; an elongated flat common contact long enough to span aplurality of the spaced individual contacts; and a supporting arm forthe common contact integral therewith and fixed to the carrier tosupport the common contact from the carrier in front of the adjacentindividual contacts, said supporting arm being flat and coplanar withthe individual contacts and spaced from the nearest thereof and holdingthe common contact coplanar with the individual contacts in edgewisespaced relation to the ends of those of said individual contacts spannedby the common contact.

10. In a multiposition electric switch, the structure of claim 9 whereinsaid supporting arm projects from the contact carrier between twoadjacent spaced individual contacts.

11. In a multiposition electric switch: a contact carrier of insulatingmaterial; a row of spaced individual con tacts fixed to the carrier andprojecting therefrom, all of said spaced individual contacts being fiatand coplanar; an elongated fiat common contact long enough to span aplurality of the spaced individual contacts; and a plurality ofsupporting arms for the common contact integral therewith and fixed tothe carrier to support the common contact from the carrier in front ofthe adjacent individual contacts, said supporting arms being Hat andcoplanar with the individual contacts and interposed between pairsthereof in edgewise spaced relation thereto, said supporting armsholding the common contact coplanar with the individual contacts inedgewise spaced relation to the ends of those of said individualcontacts spanned by the common contact.

12. A rotatry multiposition electric switch characterized by a statorcomprising: an annular member of insulating material having inner andouter edges; a plurality of individual contacts fixed to said annularmember and projecting in a circle from the inner edge thereof, all ofsaid individual contacts 'being flat and coplanar; a fiat arcuate commoncontact inside the circle of individual contacts and spanning a numberthereof; and a supporting arm for the common contact integral therewithand fixed to said annular member and projecting from its inner edge inspaced relation to the nearest of said individual contacts, saidsupporting arm being flat and coplanar with the individual contacts andholding the common contact coplanar with the individual contacts inedgewise spaced relation to the ends of those of said individualcontacts spanned by the common contact.

13. The rotary multiposition switch of claim 12, wherein the annularmember is a molding and wherein the individual contacts and thesupporting arm for the common contact are fixed to said annular memberby having portions thereof embedded in the annular member between theopposite sides thereof; and further characterized by a rotor inside theannular stator, said rotor having a circular periphery contiguous to andslidingly engaging the inner edge of the annular stator, so that therotor is journalled in the annular stator, the rotor further having agroove in and extending along its periphery, the stator contacts beingreceived in said groove and by their reception therein holding the rotorassembled with the stator and constraining it to rotary motion withrespect to the stator; and a bridging contactor carried by the rotor andhaving contact engaging portions inside said groove located to haveswitching engagement with the common contact and different ones of theindividual contacts as the rotor is turned.

14. The rotary multiposition switch of claim 13, wherein the walls ofthe groove in the rotor have radially and angularly spaced shoulderscooperating to form a retaining pocket, and wherein the bridgingcontactor has a base portion seated in said pocket, the pocket beingslightly larger than said base portion so that the bridging contactorhas a degree of freedom to adjust itself to the stator contacts.

15. The rotary multiposition switch of claim 14, wherein the contactengaging portions of the bridging contactor are in the form of jawsshaped to grip the stator contacts therebetween.

16. The rotary multiposition switch of claim 14. wherein the rotorcomprises a pair of complementary mating sections, each having a hub anda rim encircling the hub, each of said sections being shaped to form onehalf of the groove; and securing means on the hubs of said sections tohold the sections together with their hubs abutting and their rimsspaced apart a distance slightly greater than the thickness of thestationary contacts.

17. The rotary multiposition electric switch of claim 16, wherein thecombined thickness of the two complementary mating sections does notexceed that of the annular stator; and wherein the outer faces of saidmating sections are substantially flush with the opposite sides of theannular stator and all portions of the bridging contactor lie beneathsaid outer faces of the sections.

18. The rotary multiposition electric switch of claim 17, wherein thecomplementary mating sections are identical moldings.

19. The rotary multiposition electric switch of claim 16, wherein therim and hub of each rotor section are connected by spokes, the spacesbetween which afiord access to the contact portions of the bridgingcontactor.

References Cited in the file of this patent UNITED STATES PATENTS2,447,718 Simpson Aug. 24, 1948 2,734,257 Ionsson Feb. 14, 19562,755,347 Allison July 17, 1956 2,805,291 Eikhorst Sept. 3, 19572,807,868 Knapp Oct. 1, 1957 2,870,274 Thias Jan. 20, 1959 2,870,276Gelzer Jan. 20, 1959 FOREIGN PATENTSv 103,183 Australia Feb. 17, 19381,061,083 France Nov. 25, 1953 1,077,397 France Apr. 28, 1954

